MicroBiology Chapter 13

CD4 is predominantly found on ______.

helper t cells

Genes that play a role in proper cell division but may also play a role in some types of cancer are called (oncogenes/protooncogenes/promoters).

protooncogenes

Arboviruses are _________.

viruses that are transmitted to humans via the bite of an arthropod.

A horror movie portrays victims of biological warfare with uncontrolled bleeding from the eyes, mouth, nose, ears, and anus. What actual virus causes these symptoms?

ebola

In a lytic cycle of replication, release of phages involves _____. A. exocytosis of phages across the cell wall B. keeping the host cell alive C. the bacterial cell bursting open D. contact with another uninfected bacterium

C. the bacterial cell bursting open

In which stage does formation of mature viruses occur? A. Assembly B. Attachment C. Release D. Penetration E. Biosynthesis

A. Assembly

What portion of bacteriophage T4 enters E. coli? A. Only the T4 genome enters the bacterial cell. B. Only the tail fibers penetrate into the interior of the bacterial cell. C. No portion of phage T4 actually enters the bacterial cell. D. The entire phage enters into the bacterial cell.

A. Only the T4 genome enters the bacterial cell.

In which stage is the viral DNA introduced into the cell? A. Penetration B. Assembly C. Release D. Attachment E. Biosynthesis

A. Penetration

During a lytic replication cycle, what action does a phage take to ensure that its host bacterium does NOT continue synthesizing cellular molecules? A. Phage enzymes degrade the bacterial DNA. B. The host DNA is released from the cell. C. The phage integrates its DNA into the host cell DNA. D. A phage traps the host DNA in an endosome.

A. Phage enzymes degrade the bacterial DNA.

How is the lytic cycle different from the lysogenic cycle with respect to the infected host cell? A. The host cell dies during the lytic stage. B. The viral DNA may integrate into the host genome during the lytic stage. C. The host cell can only divide during the lytic stage. D. The host cell is allowed to live during the lytic stage.

A. The host cell dies during the lytic stage.

What would be the fate of a lytic bacteriophage if the host cell died prior to the assembly stage? A. The virus would not be able to infect new hosts. B. The virus would infect new hosts. C. The cell could still be revived by the virus.

A. The virus would not be able to infect new hosts.

Lysogenic viral DNA integrating into the host genome is referred to as A. a prophage. B. lysogeny. C. lytic. D. induction.

A. a prophage

During the lysogenic cycle, it is possible for integrated phage genes to change the characteristics of the host cell. This is known as _____. A. lysogenic conversion B. transduction C. induction D. synthesis

A. lysogenic conversion

From which phrase is the term "prions" derived? A. Protein infections B. Proteinaceous infectious particles C. Particles of infection D. Protein infection of the nervous system

B. Proteinaceous infectious particles

What is the function of the structural elements of a virus? A. To use all of the cell proteins B. To package and protect the viral genome C. To provide a source of energy for the virus

B. To package and protect the viral genome

What factor may induce a prophage to enter the lytic cycle? A. replication of the host bacterium B. UV light C. Infection by an additional phage D. burst time

B. UV light

Contact between a phage and its bacterial host occurs by _____. A. using jet-style propulsion B. a random collision C. using flagella D. using phage tail fibers

B. a random collision

Which step of viral replication are antibodies directly preventing? A. synthesis B. attachment C. uncoating D. assembly

B. attachment

A cell is infected with a virus carrying an oncogene sequence in its genome. What process may occur if the oncogene is expressed in the infected cell? A. lysogeny B. neoplasia C. lysis D. latency E. both lysis and neoplasia

B. neoplasia

A major difference between the lytic and lysogenic cycles of phage replication is that during the lysogenic phase _____. A. the bacterial cell is broken open, destroying the cell B. the phage genome inserts itself into the host genome C. the host DNA is degraded D. attachment of the phage involves a random collision

B. the phage genome inserts itself into the host genome

What is the fate of the prophage during the lysogenic stage? A. It is packaged into viral proteins and maintained until the host is exposed to an environmental stress. B. It is degraded by the activity of host defense enzymes. C. It is copied every time the host DNA replicates. D. It is released from the cell by lysing the cell.

C. It is copied every time the host DNA replicates.

Enveloped viruses have a layer of lipids surrounding their capsid. This envelope is made mostly of host cell membrane. In which step does the virus acquire this envelope? A. synthesis B. attachment C. release D. assembly

C. Release

Which disease did Stanley Prusiner first identify as being caused by prions? A. Fatal familial insomnia B. Mad cow disease C. Scrapie D. Kuru

C. Scrapie

How are prions different from other infectious agents? A. They cannot replicate. B. They lack protein. C. They lack nucleic acid. D. They cause neurological disease.

C. They lack nucleic acid.

In what year did Stanley Prusiner discover prions? A. 1928 B. 1979 C. 1997 D. 1982

D. 1982

Which of the following events might trigger induction of a temperate bacteriophage? A. An infected cell entering the logarithmic phase of growth B. Bacterial conjugation C. Normal cell division of an infected cell D. Exposure to UV light

D. Exposure to UV light

What occurs during viral uncoating? A. The nucleic acid breaks apart, allowing for translation. B. The viral envelope is released. C. The viral proteins are synthesized. D. The capsid breaks apart, releasing the viral genome.

D. The capsid breaks apart, releasing the viral genome.

Once entry into the bacterial cell has been achieved, the next step in a lytic replication cycle is _____. A. attachment B. assembly C. release D. synthesis

D. synthesis

The host DNA is usually degraded during which stage? A. Assembly B. Penetration C. Release D. Attachment E. Biosynthesis

E. Biosynthesis

Epstein-Barr virus ____________.

can be asymptomatic, causes mono, and can cause cancer.

Human herpesvirus 2 _____________.

can cause genital herpes, may infect a baby at birth, and causes about 10% of cold sores.

How are viruses different from cells? A. They do not contain protein. B. They do not contain enzymes. C. They require a host in order to reproduce. D. They do not contain genetic material.

C. They require a host in order to reproduce.

What disease does the human herpesvirus-1 cause? A. canker sores B. chancres C. cold sores or fever blisters D. infectious mononucleosis

C. cold sores or fever blisters